KR101844969B1 - Ordered porous titanium nitride, method for preparing the same, and lithium-air battery comprising the same - Google Patents

Abstract

The present invention relates to a porous titanium nitride in which a plurality of pores are formed. Accordingly, the porous titanium nitride of the present invention can be used as an air electrode of a lithium-air battery and ultimately can be utilized in a lithium-air battery of excellent performance having improved capacity, cycle characteristics and stability by using no carbon have.

Description

FIELD OF THE INVENTION [0001] The present invention relates to porous titanium nitride, a method for producing the same, and a lithium-air battery including the porous titanium nitride,

More particularly, the present invention relates to a porous titanium nitride which can be used as an air electrode, a method for producing the porous titanium nitride, and a method for producing the porous titanium nitride having a lithium- Air battery.

In recent years, the development of technologies for converting automobile energy sources from gasoline and light oil to electrical energy has been attracting attention, in light of an increase in carbon dioxide emissions due to the consumption of fossil fuels and a rapid change in crude oil prices. Electric vehicles have been put into practical use. For long-distance driving, it is required to increase the capacity and energy density of lithium-ion batteries, which are storage batteries. However, current lithium ion batteries have a disadvantage in that it is difficult to travel long distances due to the limited battery capacity. Therefore, lithium air cells, which are theoretically larger in capacity and higher in energy density than lithium ion batteries, are attracting attention.

A lithium-oxygen battery is a storage system that stores and releases energy using the reaction of oxygen and lithium in the air. However, there are problems such as low charge / discharge efficiency, short lifetime characteristics, and instability for commercialization. Generally, a high-surface-area carbon-based electrode is used as a cathode support for maximizing the reaction between lithium and oxygen for a high-capacity battery. The carbon-based electrode has high electrical conductivity and excellent oxygen reduction activity, but decomposes in the voltage range of 3.5 V or more during charging of the lithium-air battery and reacts with lithium-oxide and the like to form lithium carbonate (Li ₂ CO ₃ ) and carboxylates And so on. This has a serious effect on the life characteristics of the battery. Therefore, it is necessary to develop a non-carbon-based electrode material exhibiting high electrical conductivity, wide specific surface area and excellent chemical / physical stability.

Considering these points, TiN is considered as a non-carbon based electrode material having high conductivity and excellent physical stability. However, there are many difficulties in designing a material having a porous structure while having a wide specific surface area with TiN. For example, attempts have been made to use mesoporous silica as a template to make TiN with a high surface area mesoporous structure. Since the sol-gel reaction to synthesize TiN is difficult, TiO ₂ / silica composite is prepared by filling the titanium precursor inside the mesoporous silica with heat treatment and then converted to TiN by high temperature heat treatment under ammonia gas atmosphere A method has been tried. However, _{TiO 2 (anatase phase: 3.78g cm} - 3) and TiN: Due to the large density difference between the (cubic phase 5.22g cm ^-3) is not formed in the TiN structure connected to the internal mesoporous silica in the form of nanoparticles And the mesoporous structure of pure TiN could not be made because the nanostructure could not be maintained after silica removal.

Another method for synthesizing a mesoporous TiN is to use a carbon nitride (C ₃ N ₄ ) having a mesoporous structure. When the carbon nitride is filled with a titanium precursor and heat-treated in an inert gas atmosphere, the carbon nitride is converted to carbon, and at the same time, TiN is formed as nitrogen precursor. However, this exo-templating method has the disadvantage of using two casting methods to fill the carbon nitride of the nanostructures synthesized using the casting method, as well as forming a carbon-mixed TiN / C composite.

An object of the present invention is to provide a porous titanium nitride synthesized by a self-assembly method using a block copolymer and an ammonia heat treatment method, and by applying it as an electrode material of a lithium-air battery, And excellent cycle characteristics and stability.

According to an aspect of the invention, there is provided a porous titanium nitride (TiN) comprising a plurality of pores.

The pores may be in the form of a tunnel.

And the tunnel-like pores may be arranged in parallel to each other in the longitudinal direction

The surface of the tunnel-like pores cut perpendicular to the longitudinal direction may be any one selected from a circle, an ellipse, and a polygon.

According to another aspect of the present invention,

A gas diffusion layer; And

And a catalyst composite disposed on the gas diffusion layer, the catalyst composite including the porous titanium nitride and the polymer binder.

The gas diffusion layer may include any one of carbon paper, stainless steel mesh, and carbon nanotube paper.

The polymer binder may be selected from the group consisting of polyvinylidene fluoride, polytetrafluoroethylene, carboxylmethyl cellulose, polyethylene, polyethylene oxide, Nafion, And may be any one of polymethyl methacrylate.

According to another aspect of the present invention,

cathode;

The air electrode;

An electrolyte between the cathode and the cathode; And

And a separator between the negative electrode and the negative electrode.

Wherein the electrolyte is selected from the group consisting of lithium iodide (LiI), lithium bromide, Tetrathiafulvalene (TTF), 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) , And trisdiethylaminophenylamine (tris [4- (diethylamino) phenyl] amine, TDPA).

Preferably, the catalyst may comprise lithium iodide (LiI).

The separation membrane may include at least one selected from glass fiber, polyethylene, and polypropylene.

And a polyurethane (PU) separator may be further disposed on the separator between the separator and the cathode.

According to another aspect of the present invention,

Titanium oxide precursor, an amphiphilic block copolymer, and a solvent to prepare a mixed solution, and evaporating-induced self-assembly (EISA) of the mixed solution to prepare a block copolymer-titanium oxide complex (Step a);

(B) preparing a porous titanium oxide having a plurality of pores by heat treating the block copolymer-titanium oxide composite; And

Treating the porous titanium oxide in an ammonia (NH ₃ ) atmosphere to produce a porous titanium nitride having a plurality of pores (step c); and a step (c) of preparing the porous titanium nitride.

After step a, the block copolymer-titanium oxide composite may be crosslinked to prepare a crosslinked block copolymer-titanium oxide composite (step a ').

The titanium precursor may be any one of Titanium isopropoxide, Titanium chloride, and Titanium butoxide.

Wherein the amphiphilic block copolymer is selected from the group consisting of poly (ethylene oxide) -block-poly (styrene), poly (styrene) -block-poly methyl methacrylate) and poly (isoprene) -block-poly (ethylene oxide).

The solvent may be any one selected from tetrahydrofuran, chloroform and dioxane.

The evaporation-induced self-assembly of step a can be carried out at 30 to 80 占 폚.

The heat treatment of step b may be carried out at a temperature of 400 to 600 占 폚.

The heat treatment of step c may be carried out at a temperature of 600 to 800.

The present invention provides a porous titanium nitride synthesized by a self-assembling method using a block copolymer and an ammonia heat treatment method, and when it is applied to an electrode material of a lithium-air battery, a high capacity, excellent cycle characteristics, There is a visible effect.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of the synthesis of the porous titanium nitride of the present invention.
2 shows the results (a), SAXS analysis results (b) and XRD analysis results (c) showing the nitrogen adsorption-desorption curves and the pore size distribution related thereto according to Example 1 and Comparative Example 1. FIG.
3 shows an SEM image (a), a TEM image (b) and an HR-TEM image (c) according to Example 1. Fig.
Fig. 4 shows SEM images (a), (b) and TEM image (c) according to Comparative Example 4. Fig.
FIG. 5 shows the results of Raman spectrum analysis according to Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. FIG.
Fig. 6 shows the results of constant current charging and discharging of the lithium-air battery according to Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4. Fig.
FIG. 7 shows the results of XPS analysis according to Example 1 and Comparative Example 3. FIG.
8 shows the XRD analysis results before and after the cycle according to Example 1. Fig.
9 shows an SEM image (a) for the by-product formation according to the cycle duration of Example 1, and an XPS analysis result (b) for estimating the byproducts generated after 150 cycles.
10 shows an SEM image of by-product formation according to the cycle duration of Comparative Example 3. Fig.
11 is a graph showing the results of XRD analysis (c) of the constant current charge / discharge curve (a) of the battery when the LiI was added according to Test Example 8, the cycle characteristics (b) .

The invention is capable of various modifications and may have various embodiments, and particular embodiments are exemplified and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Furthermore, terms including an ordinal number such as the first, second, etc. to be used below can be used to describe various elements, but the constituent elements are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Also, when an element is referred to as being "formed" or "laminated" on another element, it may be directly attached or laminated to the front surface or one surface of the other element, It will be appreciated that other components may be present in the < / RTI >

The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The porous titanium nitride of the present invention may include a plurality of pores.

The pores may be in the form of a tunnel.

The tunnel-like pores may be arranged in parallel to one another in the longitudinal direction.

The surface of the tunnel-like pores cut perpendicular to the longitudinal direction may be any one selected from a circle, an ellipse, and a polygon. Also, specific examples of the polygon may be a square, a pentagon, a hexagonal, a hexagon, or an octagon, and may be hexagonal, but are not limited thereto.

The air electrode of the present invention comprises a gas diffusion layer; And a catalyst composite disposed on the gas diffusion layer, the catalyst composite including the porous titanium nitride and the polymer binder.

The gas diffusion layer may be any one of a stainless steel mesh and a carbon nanotube paper.

The polymer binder may be selected from the group consisting of polyvinylidene fluoride, polytetrafluoroethylene, carboxylmethyl cellulose, polyethylene, polyethylene oxide, Nafion, And may be any one of polymethyl methacrylate.

The lithium-air battery of the present invention comprises a negative electrode; The air electrode; An electrolyte between the cathode and the cathode; And a separator between the cathode and the cathode.

Wherein the electrolyte is selected from the group consisting of lithium iodide (LiI), lithium bromide, Tetrathiafulvalene (TTF), 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) , And trisdiethylaminophenylamine (tris [4- (diethylamino) phenyl] amine, TDPA).

Preferably, the catalyst may comprise lithium iodide (LiI).

The separation membrane may include at least one selected from glass fiber, polyethylene, and polypropylene.

And a polyurethane (PU) separator may be further disposed on the separator between the separator and the cathode.

The production method of the porous titanium nitride of the present invention will be described.

First, a mixed solution is prepared by mixing a titanium precursor, an amphiphilic block copolymer, and a solvent, and the mixed solution is subjected to evaporation-induced self-assembly (EISA) to prepare a block copolymer-titanium oxide composite (Step a).

After step a, the block copolymer-titanium oxide composite may be crosslinked to prepare a crosslinked block copolymer-titanium oxide composite (step a ').

The titanium precursor may be any one of Titanium isopropoxide, Titanium chloride, and Titanium butoxide.

Wherein the amphiphilic block copolymer is selected from the group consisting of polyethylene oxide-block-poly (styrene), poly (styrene) -block-poly (methyl methacrylate) ) And poly (isoprene) -block-poly (ethylene oxide).

The solvent may be any one selected from tetrahydrofuran, chloroform and dioxane.

The evaporation-induced self-assembly of step a can be carried out at a temperature of 30 to 80 占 폚.

Next, the block copolymer-titanium oxide composite is heat-treated to produce a porous titanium oxide having a plurality of pores (step b).

The heat treatment of step b may be carried out at a temperature of 400 to 600 占 폚.

Next, the porous titanium oxide is heat-treated in an ammonia (NH ₃ ) atmosphere to produce a porous titanium nitride having a plurality of pores (step c).

The heat treatment of step c may be carried out at a temperature of 600 to 800.

[Example]

reagent

(2-bromoisobutyrylbromide), pentamethyldiethylenetriamine (PMDETA), dichloromethane (CH ₂ Cl ₂ ), triethylamine (TEA ), Styrene, methanol, copper bromide (CuBr), phenol, formaldehyde solution (37 wt% in H ₂ O), titanium isopropoxide, TTIP), hydrochloric acid (37 wt% in water), tetrahydrofuran (THF), commercial TiN (c-TiN), tetraethylorthosilicate (TEOS), polyvinylidene fluoride (Vinylidene fluoride), PVDF, N-methyl-2-pyrrolidone (NMP), lithium perchlorate (LiClO ₄ ), and 1,2-dimethoxyethane 1,2-dimethoxyethane, DME), and tetraethyleneglycol dimethyl ether ene glycol dimethyl ether, TEGDME) was purchased from Sigma-Aldrich and used immediately after purchase without purification. Phenol-formaldehyde resin was synthesized by basic polymerization synthesis of phenol and formalin. Structural derivatives of polyethylene oxide-polystyrene block copolymer (PEO- b -PS) was synthesized using the atom transfer radical polymerization (atomic transfer radical-polymerization, ATRP) method, the molecular weight of the PEO block of the two blocks is 5kg ^mol-1 .

Production Example 1: phenol formaldehyde resin

Phenol formaldehyde resin was prepared by basic polymerization method. 12.2 g (130 mmol) of phenol was added to the inside of the flask and dissolved at 42 DEG C, and then 2.6 g (13 mmol) of 20 wt% sodium hydroxide was slowly added thereto. Then 21 g of a 37 wt% formaldehyde solution was added. The temperature of the reactor was maintained at 70 DEG C for one hour and then cooled. The solution was titrated with hydrochloric acid (HCl) until it became a neutral solution to prevent further polymerization. After drying at 50 ° C in a vacuum oven to remove moisture, tetrahydrofuran (THF) solution was added to precipitate sodium chloride to remove tetrahydrofuran (THF).

Preparation Example 2 Preparation of poly (ethylene oxide) -poly (styrene) block copolymer

A polyethylene oxide - polystyrene block copolymer was prepared by atom transfer radical polymerization. To make PEO-Br, 20 g of polyethylene oxide polymer (mPEO-OH) was dissolved in dichloromethane (100 ml) and 5 ml of triethylamine (TEA) was added. After stirring at 0 ° C, 1.48 ml of 2-bromoisobutylbromide was added dropwise. Thereafter, the reaction was maintained at room temperature for 8 hours. The resultant was extracted / purified using DI water and ether, and dried in vacuum.

20 g (192 mmol) of styrene, 0.071 g (0.5 mmol) of copper bromide and 0.085 g (0.5 mmol) of pentamethyldiethylenetriamine (PMDETA) were added to 2.539 g (0.5 mmol) of PEO-Br. After making the vacuum atmosphere, the temperature of the reactor was elevated to 110 캜 and maintained for 12 hours. The resultant was dissolved in tetrahydrofuran (THF) and then passed through an alumina column to remove the copper catalyst to prepare a polyethylene oxide-polystyrene block copolymer (PEO-b-PS).

Example 1: Preparation of m-TiN

A schematic diagram of the synthesis of Example 1 is shown in Fig. 1, 1.2 g of titanium isopropoxide (TTIP) was dissolved in 4.4 g of a polymer solution (polyethylene oxide-polystyrene block copolymer (PEO- b- PS, 25 kg mol ^-1 ): hydrochloric acid ): Water (H ₂ O): tetrahydrofuran (THF) = 1: 1.1: 1.9: 18, mass ratio). After stirring for one hour, the solution was evaporated on a glass plate (50 ° C). After the evaporation of the solvent, the mixture was crosslinked in an oven at 100 ° C for 12 hours, heated to 500 ° C at a rate of 1 ° C / min, and then heat-treated in air for 3 hours. After cooling to room temperature after heating, the temperature was raised to 700 ° C at a rate of 1 ° C / min, and mesoporous TiN (m-TiN) was synthesized through heat treatment for 10 hours.

Comparative Example 1: m-TiO having pores of 22 nm ₂ Manufacturing

In the same manner as in Example 1 except that the heat treatment was carried out in the same manner as in Example 1 except that the heat treatment was carried out after the heat treatment in Example 1 and the temperature was raised to 700 ° C at a rate of 1 ° C / Porous titanium oxide (mesoporous TiO ₂ , m-TiO ₂ ) was synthesized.

Comparative Example 2: m-TiO having pores of 33 nm ₂ Manufacturing

In Example 1, 1.2 g of titanium isopropoxide (TTIP) was added to 4.4 g of a polymer solution (polyethylene oxide-polystyrene block copolymer (PEO- b- PS, 25 kg mol ^-1 ): hydrochloric acid (HCl) H ₂ O): tetrahydrofuran (THF) = 1: 1.1: 1.9: 18, mass ratio) of the polymer solution, 4.4g of titanium isopropoxide (TTIP) of 1.1g instead of the input (polyethylene oxide-block- (PEO- b- PS, 25 kg mol ^-1 ): hydrochloric acid (HCl): water (H ₂ O): tetrahydrofuran (THF) = 1: 1.1: 1.9: Mesoporous titanium oxide (mesoporous TiO ₂ , m-TiO ₂ ) was synthesized in the same manner as in Example 1.

Comparative Example  3: Structural regularity Mesoporous  Carbon (Ordered Mesoporous  Carbon, OMC )

(Polyethylene oxide-polystyrene block copolymer (PEO- b- PS, 30 kg mol ^-1 ): hydrochloric acid (HCl) was added to a solution of 4 g of a phenol formaldehyde resin and 0.17 g of tetraethyl orthosilicate : H ₂ O: tetrahydrofuran (THF) = 1: 0.2: 0.34: 18, mass ratio). The solution was dried in a dish at 60 ° C and then heat-treated in a nitrogen atmosphere at 800 ° C. After the heat treatment, the substrate was washed with 10 wt% hydrogen fluoride (HF) solution to remove silicon dioxide (SiO ₂ ).

Comparative Example 4: Commercial titanium nitride (commercial TiN, c-TiN)

Commercial TiN (c-TiN) was a Sigma-Aldrich product and was used immediately after purchase without purification.

Example 2: Preparation of air electrode

M-TiN prepared in Example 1 was mixed with polyvinylidene fluoride (PVDF) in a mass ratio of 95: 5, and N-methyl-2-pyrrolidone (NMP) was added thereto to prepare a slurry. The prepared slurry was coated on a gas diffusion layer (TGPH-090, 16 mm diameter, Toray, Japan). Thereafter, it was dried at 70 캜 under a vacuum condition for 12 hours to prepare an air electrode.

Device Example 1: Manufacture of lithium air cell

A 600 μm thick lithium (Honjo, Japan) was used as a cathode for the fabrication of the cell, and a glass fiber membrane (GF / D, Whatman, USA) was used as a separator. As the electrolyte, 1M LiClO ₄ in TEGDME (Aldrich, USA) was used.

Air electrode A 2032 coin cell was fabricated in the order of cathode, separator, electrolyte, and cathode using the cathode according to Example 1, the cathode, the separator, and the electrolyte.

Device Example 2: Preparation of lithium-air battery to which lithium iodide (LiI) was added

Except that 1 M of LiClO ₄ in TEGDME (Aldrich, USA) in which lithium iodide (LiI) was added at a concentration of 0.05 M instead of 1 M of LiClO ₄ in TEGDME (Aldrich, USA) 2032 coin cells were prepared in the same manner as in Example 1.

Device Example  3: Lithium iodide ( LiI ) And polyurethane (PU) membranes were prepared.

(GF / D, Whatman, USA) as well as a glass fiber membrane (glass fiber membrane, GF / D, Whatman, USA) Except that a polyurethane (PU) separator (En-Ha Mechanics) was additionally used between the anode (GF / D, Whatman, USA) and the lithium metal (cathode) Respectively.

Device Comparative Example 1

Coin cells of the 2032 standard were prepared in the same manner as in Example 1 except that m-TiO ₂ prepared according to Comparative Example 2 was used instead of m-TiN prepared according to Example 1.

Device Comparative Example 2

A coin cell of the 2032 standard was prepared in the same manner as in Example 1 except that the OMC produced in accordance with Comparative Example 3 was used instead of the m-TiN produced in Example 1.

Device comparison example  3

A 2032 coin cell was prepared in the same manner as in Example 1 except that the c-TiN used in Comparative Example 4 was used instead of the m-TiN produced according to Example 1.

Device Comparative Example 4

A coin cell of the 2032 standard was prepared in the same manner as in Example 2 except that OMC prepared according to Comparative Example 3 was used instead of m-TiN prepared according to Example 1.

[Test Example]

M-TiN, the mesoporous titanium oxide of Comparative Example 2, or the lithium-air battery containing the same was referred to as m-TiO _{2 ,} the structure of Comparative Example 3 Regularly mesoporous carbon or a lithium-air cell containing the same was designated as OMC, the comparative titanium nitride of Comparative Example 4, or a lithium-air cell containing the same, as c-TiN.

Test Example 1: Nitrogen adsorption-desorption curve, SAXS and XRD analysis

X-ray diffraction (XRD) analysis was performed using a Bruker D8 Advanced XRD / micro XRD, Bruker / Rigaku and USA / Japan (Cu Kα (λ = 0.15406 nm) ray scattering (SAXS) was measured on a 4C line of Pohang radiation accelerator. Nitrogen adsorption / desorption was analyzed using TriStar 3020, Micrometrics, USA.

FIG. 2 is a graph showing the results of (a), SAXS analysis results (b), and XRD analysis results (c) showing the nitrogen adsorption / desorption curves for the products prepared in Example 1 and Comparative Example 1, .

According to FIG. 2 (a), both Example 1 and Comparative Example 1 exhibited type-IV hysteresis and a steep increase in the adsorption curve at P / P _o values of ~ 0.9 and ~ 0.95. This means that both Example 1 and Comparative Example 1 have a mesoporous structure.

The pore size was measured by the Barrett-Joner-Halenda (BJH) method, and it was confirmed that the pore size was further increased after heat treatment at 37 nm in Example 1 and 23 nm in Comparative Example 1. It is assumed that this is due to shrinkage of the structure at high temperature and structural change from oxide to nitride.

The specific surface area and pore volume measured by the Brunauer-Emmett-Teller (BET) method were 58 m ² g ^-1 and 0.36 cm ³ g ^{-1 in} Example 1, 65 m ² g ^-1 and 0.3 cm ^{2 in} Comparative Example 1, ³ g ^-1 .

2 (b), the SAXS (Small-angle X-ray scattering) pattern corresponds to (100), (200), (210) and (300) Peaks appear to be 2-D hexagonal structures. In the case of Comparative Example 1, the x value of the main peak increased, which means that the interval between regular patterns was reduced. This is presumed to be due to organic (PS block) removal and growth of TiO ₂ crystals. In the case of Example 1, the x value of the main peak decreases again, which is similar to the increase of the pore size in the nitrogen adsorption experiment.

According to FIG. 2 (c), the crystal structure of anatase TiO ₂ (JCPDS #: 78-2486) of Comparative Example 1 was completely converted to cubic TiN (JCPDS #: 87-0633) of Example 1 through XRD results. Calculating the crystal size through the Debye-Scherrer equation shows that it increases from 15.9 nm (Comparative Example 1) to 16.3 nm (Example 1).

Test Example 2: SEM and TEM image analysis

In order to analyze the structure of the sample, field-emission scanning electron microscopy (FE-SEM, Hitachi S-4200 / S-4800, Japan) USA) was used.

3 (a) is an SEM image of Example 1, (b) is a TEM image of Example 1, and (c) is an HR-TEM image of Example 1. Fig.

4 (a) and 4 (b) show SEM images of Comparative Example 4, and FIG. 4 (c) shows TEM images of Comparative Example 4.

3 (a), 3 (b) and 3 (c), it was confirmed that the hexagonal mesoporous structure of the product of Example 1 was retained even after the ammonia heat treatment.

4 (a) and 4 (b), it was confirmed that the material of Comparative Example 4 had no particle size and pore distribution ranging from several hundred nanometers to several micrometers.

The c-TiN has a particle size ranging from several hundred nanometers to several micrometers and has a shape with no distribution of pores. Therefore, it can be confirmed that the reaction area is small because the surface area is lower than that of the m-TiN having the pore structure.

Test Example 3: Raman spectrum analysis

The results of the analysis are shown in FIG. 5, and specifically, FIG. 5 (a) is a graph showing the results of analysis 1, Comparative Example 2, and Comparative Example 4, and (b) shows the results of Raman spectrum analysis for Comparative Example 3. FIG.

According to FIG. 5 (a), the products of Example 1, Comparative Example 2, and Comparative Example 4 did not show G-band and D-band, indicating that no carbon was present. In addition, the Raman spectrum of Comparative Example 4 was not the same as that of Example 1, and it was confirmed that an oxide layer was formed on the surface due to surface oxidation through the presence of Rutile phase.

However, according to FIG. 5 (b), the product of Comparative Example 3 was found to contain carbon through two bands of 1590 cm ^-1 (G-band) and 1340 cm ^-1 (D-band). In addition, it was confirmed that a large number of defects were present in carbon through the presence of the D-band in Comparative Example 3.

Test Example 4: Constant current charge / discharge curve of lithium-air battery

Fig. 6 (c) is a device comparison example 1, (b) is a device comparison example 1, (d) is a device comparison example 2, and Fig. 6 (a) shows a constant current charge / discharge result of the lithium- As the cycle continued, the device of Comparative Example 2 showed a decrease in capacity, whereas the device of Example 1 showed an increase in capacity continuously and a higher capacity than that of Comparative Example 2 until reaching 100 cycles. This is presumed to be due to activation of the electrode / oxygen / electrolyte three-phase interface as the cycle continues. In the device comparison example 1 and the device comparison example 3, as the cycle continued, the capacity increased slightly, but the capacity was much lower than that of the device example 1. In Comparative Example 3 using commercial TiN, it is considered that the surface area of the electrode material is low and the capacitance is low because the particles are large and the interconnectivity is low.

Test Example 5: X-ray photoelectron spectroscopy (XPS) analysis

X-ray photoelectron spectroscopy (XPS, K-alpha, Thermo VG Scientific, England) with an Al-Kα line as the X-ray source was used to analyze the chemical state of the material.

FIG. 7A is an XPS analysis graph of the pristine state of the element embodiment 1 and the element comparison example 3, and FIG. 7B is an XPS analysis graph of the element embodiment 1 after 150 cycles.

In FIG. 7 (a), some oxynitride (TiO _x N _y ) was formed. This shows that the device of Example 1 has a higher capacity than the device of Comparative Example 3 because it forms a highly conductive film.

7 (b), it was confirmed that the surface of the device Example 1 was stably maintained after 150 cycles.

Test Example 6: Evaluation of stability of m-TiN

Bruker D8 Advanced XRD / micro XRD, Bruker / Rigaku, USA / Japan) was used for X-ray diffraction analysis (XRD).

8 is a result of XRD analysis before and after the cycle to evaluate the stability of the element Embodiment 1. Li ₂ O _{2, which} is a reaction product of the lithium-air battery, is reversibly formed / decomposed and TiN crystal is maintained.

Test Example 7: Confirmation of the formation of by-products as the cycle continues

9 (a) is an SEM image in which byproducts are formed on the surface during 150 cycles of the device Example 1, and FIG. 9 (b) is a SEM image of the carbonaceous material after 150 cycles It was found that there was a byproduct which was presumed to be carboxylates.

FIG. 10 shows an SEM image in which byproducts are formed on the surface during 100 cycles of the device comparison example 2. In the device comparison example 2, a larger amount of by-product is formed than in the device example 1.

Test Example 8: Determination of cycle characteristics

11 (a) is a constant current charge / discharge curve of a battery when LiI, a redox mediator, is added to prevent the production of by-products due to electrolyte separation at a high voltage. When LiI was added, the charging voltage was lowered.

Fig. 11 (b) shows the cycle results of the lithium ion battery of the element embodiments 1 to 3 and the element comparison examples 2 and 4. Fig. Device Example 1 and Device Example 2 exhibited better cycle characteristics than Device Comparative Example 2 and Device Comparative Example 4, but cross-over oxygen or water as a reaction by-product passed to the cathode, causing a side reaction, resulting in poor cycle stability. Therefore, polyurethane (PU) was used as a separator to prevent side reactions between lithium metal and water or cross-over oxygen. Thus, the device of Example 3 exhibited the best cycle characteristics.

11 (c), it was found that LiOH was not formed by protecting the lithium anode in the third embodiment.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

Claims (20)

cathode;
Air pole;
An electrolyte between the cathode and the cathode;
A separator between the cathode and the cathode; and
A polyurethane (PU) separator on the separator, the separator being positioned between the separator and the cathode; / RTI >
The air electrode being a gas diffusion layer; And a catalyst composite disposed on the gas diffusion layer, the catalyst composite including porous titanium nitride and a polymeric binder,
Wherein the porous titanium nitride is a porous titanium nitride (TiN) including a plurality of pores, the pores are in the form of a tunnel, the pores in the form of a tunnel are arranged in parallel to one another in the longitudinal direction, wherein the plane of the tunnel-shaped pores cut perpendicular to the longitudinal direction is hexagonal (hexagonal). delete delete delete delete The method according to claim 1,
Wherein the gas diffusion layer comprises any one selected from the group consisting of carbon paper, stainless steel mesh, and carbon nanotube paper. The method of claim 1, wherein
The polymer binder may be selected from the group consisting of polyvinylidene fluoride, polytetrafluoroethylene, carboxylmethyl cellulose, polyethylene, polyethylene oxide, Nafion, Wherein the lithium-air battery is one selected from the group consisting of polymethyl methacrylate. delete The method according to claim 1,
Wherein the electrolyte is selected from the group consisting of lithium iodide (LiI), lithium bromide, Tetrathiafulvalene (TTF), 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) , And trisdiethylaminophenylamine (tris [4- (diethylamino) phenyl] amine, TDPA). 10. The method of claim 9,
Characterized in that the catalyst comprises lithium iodide (LiI). The method according to claim 1,
Wherein the separator comprises at least one selected from the group consisting of glass fiber, polyethylene, and polypropylene. delete The method according to claim 1,
The porous titanium nitride
Titanium oxide precursor, an amphiphilic block copolymer, and a solvent to prepare a mixed solution, and evaporating-induced self-assembly (EISA) of the mixed solution to prepare a block copolymer-titanium oxide complex (Step a);
(B) preparing a porous titanium oxide having a plurality of pores by heat treating the block copolymer-titanium oxide composite; And
Treating the porous titanium oxide in an ammonia (NH ₃ ) atmosphere to produce a porous titanium nitride having a plurality of pores (step c);
Wherein the porous titanium nitride is produced by a process for producing a porous titanium nitride. 14. The method of claim 13, wherein the process for preparing the porous titanium nitride comprises:
5. The lithium-air battery according to claim 1, further comprising, after step (a), crosslinking the block copolymer-titanium oxide complex to prepare a crosslinked block copolymer-titanium oxide composite (step a '). 14. The method of claim 13,
Wherein the titanium precursor is any one of titanium isopropoxide, titanium chloride, and titanium butoxide. 14. The method of claim 13,
Wherein the amphiphilic block copolymer is selected from the group consisting of polyethylene oxide-block-poly (styrene), poly (styrene) -block-poly (methyl methacrylate) ) And a polyisoprene-block oxide (poly (isoprene) -block-poly (ethylene oxide). 14. The method of claim 13,
Wherein the solvent is any one of tetrahydrofuran, chloroform, and dioxane. 14. The method of claim 13,
Wherein the evaporation-induced self-assembly of step (a) is carried out at 30 to 80 占 폚. 14. The method of claim 13,
Wherein the heat treatment of step (b) is carried out at a temperature of 400 to 600 占 폚. 14. The method of claim 13,
Wherein the heat treatment in step c is performed at a temperature of 600 to 800 < 0 > C.

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